[Haskell-cafe] Contributing to http-conduit

[Myles C. Maxfield]

Alright, I'll make a small patch that adds 2 fields to SetCookie:
setCookieMaxAge :: Maybe DiffTime
setCookieSecureOnly :: Bool

I've also gotten started on those cookie functions. I'm currently writing
tests for them.

@Chris: The best advice I can give is that Chrome (what I'm using as a
source on all this) has the data baked into a .cc file. However, they have
directions in a README and a script which will parse the list and generate
that source file. I recommend doing this. That way, the Haskell module
would have 2 source files: one file that reads the list and generates the
second file, which is a very large source file that contains each element
in the list. The list should export `elem`-type queries. I'm not quite sure
how to handle wildcards that appear in the list - that part is up to you.
Thanks for helping out with this :]

--Myles

On Thu, Feb 2, 2012 at 10:53 PM, Michael Snoyman <michael at snoyman.com>wrote:

> Looks good to me too. I agree with Aristid: let's make the change to
> cookie itself. Do you want to send a pull request? I'm also
> considering making the SetCookie constructor hidden like we have for
> Request, so that if in the future we realize we need to add some other
> settings, it doesn't break the API.
>
> Chris: I would recommend compiling it into the module. Best bet would
> likely being converting the source file to Haskell source.
>
> Michael
>
> On Fri, Feb 3, 2012 at 6:32 AM, Myles C. Maxfield
> <myles.maxfield at gmail.com> wrote:
> > Alright. After reading the spec, I have these questions / concerns:
> >
> > The spec supports the "Max-Age" cookie attribute, which Web.Cookies
> doesn't.
> >
> > I see two possible solutions to this. The first is to have parseSetCookie
> > take a UTCTime as an argument which will represent the current time so it
> > can populate the setCookieExpires field by adding the Max-Age attribute
> to
> > the current time. Alternatively, that function can return an IO
> SetCookie so
> > it can ask for the current time by itself (which I think is inferior to
> > taking the current time as an argument). Note that the spec says to
> prefer
> > Max-Age over Expires.
> > Add a field to SetCookie of type Maybe DiffTime which represents the
> Max-Age
> > attribute
> >
> > Cookie code should be aware of the Public Suffix List as a part of its
> > domain verification. The cookie code only needs to be able to tell if a
> > specific string is in the list (W.Ascii -> Bool)
> >
> > I propose making an entirely unrelated package, public-suffix-list, with
> a
> > module Network.PublicSuffixList, which will expose this function, as
> well as
> > functions about parsing the list itself. Thoughts?
> >
> > Web.Cookie doesn't have a "secure-only" attribute. Adding one in is
> > straightforward enough.
> > The spec describes cookies as a property of HTTP, not of the World Wide
> Web.
> > Perhaps "Web.Cookie" should be renamed? Just a thought; it doesn't really
> > matter to me.
> >
> > As for Network.HTTP.Conduit.Cookie, the spec describes in section 5.3
> > "Storage Model" what fields a Cookie has. Here is my proposal for the
> > functions it will expose:
> >
> > receiveSetCookie :: SetCookie -> Req.Request m -> UTCTime -> Bool ->
> > CookieJar -> CookieJar
> >
> > Runs the algorithm described in section 5.3 "Storage Model"
> > The UTCTime is the current-time, the Bool is whether or not the caller
> is an
> > HTTP-based API (as opposed to JavaScript or anything else)
> >
> > updateCookieJar :: Res.Response a -> Req.Request m -> UTCTime ->
> CookieJar
> > -> (CookieJar, Res.Response a)
> >
> > Applies "receiveSetCookie" to a Response. The output CookieJar is
> stripped
> > of any Set-Cookie headers.
> > Specifies "True" for the Bool in receiveSetCookie
> >
> > computeCookieString :: Req.Request m -> CookieJar -> UTCTime -> Bool ->
> > (W.Ascii, CookieJar)
> >
> > Runs the algorithm described in section 5.4 "The Cookie Header"
> > The UTCTime and Bool are the same as in receiveSetCookie
> >
> > insertCookiesIntoRequest :: Req.Request m -> CookieJar -> UTCTime ->
> > (Req.Request m, CookieJar)
> >
> > Applies "computeCookieString" to a Request. The output cookie jar has
> > updated last-accessed-times.
> > Specifies "True" for the Bool in computeCookieString
> >
> > evictExpiredCookies :: CookieJar -> UTCTime -> CookieJar
> >
> > Runs the algorithm described in the last part of section 5.3 "Storage
> Model"
> >
> > This will make the relevant part of 'http' look like:
> >
> >     go count req'' cookie_jar'' = do
> >         now <- liftIO $ getCurrentTime
> >         let (req', cookie_jar') = insertCookiesIntoRequest req''
> > (evictExpiredCookies cookie_jar'' now) now
> >         res' <- httpRaw req' manager
> >         let (cookie_jar, res) = updateCookieJar res' req' now cookie_jar'
> >         case getRedirectedRequest req' (responseHeaders res)
> (W.statusCode
> > (statusCode res)) of
> >             Just req -> go (count - 1) req cookie_jar
> >             Nothing -> return res
> >
> > I plan to not allow for a user-supplied cookieFilter function. If they
> want
> > that functionality, they can re-implement the redirection-following
> logic.
> >
> > Any thoughts on any of this?
> >
> > Thanks,
> > Myles
> >
> > On Wed, Feb 1, 2012 at 5:19 PM, Myles C. Maxfield <
> myles.maxfield at gmail.com>
> > wrote:
> >>
> >> Nope. I'm not. The RFC is very explicit about how to handle cookies. As
> >> soon as I'm finished making sense of it (in terms of Haskell) I'll send
> >> another proposal email.
> >>
> >> On Feb 1, 2012 3:25 AM, "Michael Snoyman" <michael at snoyman.com> wrote:
> >>>
> >>> You mean you're *not* making this proposal?
> >>>
> >>> On Wed, Feb 1, 2012 at 7:30 AM, Myles C. Maxfield
> >>> <myles.maxfield at gmail.com> wrote:
> >>> > Well, this is embarrassing. Please disregard my previous email. I
> >>> > should
> >>> > learn to read the RFC *before* submitting proposals.
> >>> >
> >>> > --Myles
> >>> >
> >>> >
> >>> > On Tue, Jan 31, 2012 at 6:37 PM, Myles C. Maxfield
> >>> > <myles.maxfield at gmail.com> wrote:
> >>> >>
> >>> >> Here are my initial ideas about supporting cookies. Note that I'm
> >>> >> using
> >>> >> Chrome for ideas since it's open source.
> >>> >>
> >>> >> Network/HTTP/Conduit/Cookies.hs file
> >>> >> Exporting the following symbols:
> >>> >>
> >>> >> type StuffedCookie = SetCookie
> >>> >>
> >>> >> A regular SetCookie can have Nothing for its Domain and Path
> >>> >> attributes. A
> >>> >> StuffedCookie has to have these fields set.
> >>> >>
> >>> >> type CookieJar = [StuffedCookie]
> >>> >>
> >>> >> Chrome's cookie jar is implemented as (the C++ equivalent of) Map
> >>> >> W.Ascii
> >>> >> StuffedCookie. The key is the "eTLD+1" of the domain, so lookups for
> >>> >> all
> >>> >> cookies for a given domain are fast.
> >>> >> I think I'll stay with just a list of StuffedCookies just to keep it
> >>> >> simple. Perhaps a later revision can implement the faster map.
> >>> >>
> >>> >> getRelevantCookies :: Request m -> CookieJar -> UTCTime ->
> (CookieJar,
> >>> >> Cookies)
> >>> >>
> >>> >> Gets all the cookies from the cookie jar that should be set for the
> >>> >> given
> >>> >> Request.
> >>> >> The time argument is whatever "now" is (it's pulled out of the
> >>> >> function so
> >>> >> the function can remain pure and easily testable)
> >>> >> The function will also remove expired cookies from the cookie jar
> >>> >> (given
> >>> >> what "now" is) and return the filtered cookie jar
> >>> >>
> >>> >> putRelevantCookies :: Request m -> CookieJar -> [StuffedCookie] ->
> >>> >> CookieJar
> >>> >>
> >>> >> Insert cookies from a server response into the cookie jar.
> >>> >> The first argument is only used for checking to see which cookies
> are
> >>> >> valid (which cookies match the requested domain, etc, so site1.com
> >>> >> can't set
> >>> >> a cookie for site2.com)
> >>> >>
> >>> >> stuffCookie :: Request m -> SetCookie -> StuffedCookie
> >>> >>
> >>> >> If the SetCookie's fields are Nothing, fill them in given the
> Request
> >>> >> from
> >>> >> which it originated
> >>> >>
> >>> >> getCookies :: Response a -> ([SetCookie], Response a)
> >>> >>
> >>> >> Pull cookies out of a server response. Return the response with the
> >>> >> Set-Cookie headers filtered out
> >>> >>
> >>> >> putCookies :: Request a -> Cookies -> Request a
> >>> >>
> >>> >> A wrapper around renderCookies. Inserts some cookies into a request.
> >>> >> Doesn't overwrite cookies that are already set in the request
> >>> >>
> >>> >> These functions will be exported from Network.HTTP.Conduit as well,
> so
> >>> >> callers can use them to re-implement redirection chains
> >>> >> I won't implement a cookie filtering function (like what
> >>> >> Network.Browser
> >>> >> has)
> >>> >>
> >>> >> If you want to have arbitrary handling of cookies, re-implement
> >>> >> redirection following. It's not very difficult if you use the API
> >>> >> provided,
> >>> >> and the 'http' function is open source so you can use that as a
> >>> >> reference.
> >>> >>
> >>> >> I will implement the functions according to RFC 6265
> >>> >> I will also need to write the following functions. Should they also
> be
> >>> >> exported?
> >>> >>
> >>> >> canonicalizeDomain :: W.Ascii -> W.Ascii
> >>> >>
> >>> >> turns "..a.b.c..d.com..." to "a.b.c.d.com"
> >>> >> Technically necessary for domain matching (Chrome does it)
> >>> >> Perhaps unnecessary for a first pass? Perhaps we can trust users for
> >>> >> now?
> >>> >>
> >>> >> domainMatches :: W.Ascii -> W.Ascii -> Maybe W.Ascii
> >>> >>
> >>> >> Does the first domain match against the second domain?
> >>> >> If so, return the prefix of the first that isn't in the second
> >>> >>
> >>> >> pathMatches :: W.Ascii -> W.Ascii -> Bool
> >>> >>
> >>> >> Do the paths match?
> >>> >>
> >>> >> In order to implement domain matching, I have to have knowledge of
> >>> >> the Public Suffix List so I know that sub1.sub2.pvt.k12.wy.us can
> set
> >>> >> a
> >>> >> cookie for sub2.pvt.k12.wy.us but not for k12.wy.us (because
> >>> >> pvt.k12.wy.us
> >>> >> is a "suffix"). There are a variety of ways to implement this.
> >>> >>
> >>> >> As far as I can tell, Chrome does it by using a script (which a
> human
> >>> >> periodically runs) which parses the list at creates a .cc file that
> is
> >>> >> included in the build.
> >>> >>
> >>> >> I might be wrong about the execution of the script; it might be a
> >>> >> build
> >>> >> step. If it is a build step, however, it is suspicious that a build
> >>> >> target
> >>> >> would try to download a file...
> >>> >>
> >>> >> Any more elegant ideas?
> >>> >>
> >>> >> Feedback on any/all of the above would be very helpful before I go
> off
> >>> >> into the weeds on this project.
> >>> >>
> >>> >> Thanks,
> >>> >> Myles C. Maxfield
> >>> >>
> >>> >> On Sat, Jan 28, 2012 at 8:17 PM, Michael Snoyman <
> michael at snoyman.com>
> >>> >> wrote:
> >>> >>>
> >>> >>> Thanks, looks great! I've merged it into the Github tree.
> >>> >>>
> >>> >>> On Sat, Jan 28, 2012 at 8:36 PM, Myles C. Maxfield
> >>> >>> <myles.maxfield at gmail.com> wrote:
> >>> >>> > Ah, yes, you're completely right. I completely agree that moving
> >>> >>> > the
> >>> >>> > function into the Maybe monad increases readability. This kind of
> >>> >>> > function
> >>> >>> > is what the Maybe monad was designed for.
> >>> >>> >
> >>> >>> > Here is a revised patch.
> >>> >>> >
> >>> >>> >
> >>> >>> > On Sat, Jan 28, 2012 at 8:28 AM, Michael Snoyman
> >>> >>> > <michael at snoyman.com>
> >>> >>> > wrote:
> >>> >>> >>
> >>> >>> >> On Sat, Jan 28, 2012 at 1:20 AM, Myles C. Maxfield
> >>> >>> >> <myles.maxfield at gmail.com> wrote:
> >>> >>> >> > the fromJust should never fail, beceause of the guard
> statement:
> >>> >>> >> >
> >>> >>> >> >     | 300 <= code && code < 400 && isJust l'' && isJust l' =
> >>> >>> >> > Just $
> >>> >>> >> > req
> >>> >>> >> >
> >>> >>> >> > Because of the order of the && operators, it will only
> evaluate
> >>> >>> >> > fromJust
> >>> >>> >> > after it makes sure that the argument isJust. That function in
> >>> >>> >> > particular
> >>> >>> >> > shouldn't throw any exceptions - it should only return
> Nothing.
> >>> >>> >> >
> >>> >>> >> > Knowing that, I don't quite think I understand what your
> concern
> >>> >>> >> > is.
> >>> >>> >> > Can
> >>> >>> >> > you
> >>> >>> >> > elaborate?
> >>> >>> >>
> >>> >>> >> You're right, but I had to squint really hard to prove to myself
> >>> >>> >> that
> >>> >>> >> you're right. That's the kind of code that could easily be
> broken
> >>> >>> >> in
> >>> >>> >> future updates by an unwitting maintainer (e.g., me). To protect
> >>> >>> >> the
> >>> >>> >> world from me, I'd prefer if the code didn't have the fromJust.
> >>> >>> >> This
> >>> >>> >> might be a good place to leverage the Monad instance of Maybe.
> >>> >>> >>
> >>> >>> >> Michael
> >>> >>> >
> >>> >>> >
> >>> >>
> >>> >>
> >>> >
> >
> >
>
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